1. Field of the Invention
The invention deals with a process and a device for the removal and oxidation of organic substances from kitchen vapor contained in an extracted air stream by utilizing a ventilator generating the extracted air stream in an extracted air channel, a filter adsorbing the organic substances and a heated catalyst performing the catalytic oxidation of the organic substances.
2. Description of the Prior Art
Kitchen vapor which, in a broader sense, includes vapor generated during the manufacture and preparation of food stuff and food, for example, by bakeries or chocolate manufacturers, contains mostly organic substances which can become, depending on their concentration and the location of their emission point, a real nuisance to the surrounding area due to their smell, and can lead to other undesirable manifestations, such as, for example, deposits accompanied by mold formation.
For this reason efforts are made to capture the vapor, preferably by extracting it, and to channel the extracted air carrying the vapor through filters, among other methods, in order to remove organic substances. However, the absorption capacity of each and every filter is limited, so that, as it becomes saturated, it works less effectively and may even cease to function altogether. Filter replacement is laborious and costly, and can present a waste disposal problem.
From the German patent disclosure document 23 63 820, a device is known which channels extracted air carrying organic substances immediately following prefiltering through a heated catalyst, located upstream of a filter and a ventilator, for catalytic oxidation of the organic substances. This device has the disadvantage that the catalyst has to be heated continuously as long as the ventilator is running and supplying polluted extracted air. In order to be effective catalysts are generally provided with a large specific surface area which, however, entails transmission of energy to the extracted air stream as it flows through the catalyst, especially when the extracted air carries steam. The expenditure of energy and the costs associated with keeping the catalyst continuously at operating temperature are correspondingly high. In addition, the organic substances in the extracted air stream, occurring generally in only relatively low concentrations, can contribute only insignificantly to the heating of the catalyst through their exothermal oxidation, because of the high flow rate of extracted air.